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5e8754f9 | 1 | /* Copyright (C) 1992, 1995-2003, 2005-2016 Free Software Foundation, Inc. |
3d99e817 AK |
2 | This file is part of the GNU C Library. |
3 | ||
4 | This program is free software: you can redistribute it and/or modify | |
5 | it under the terms of the GNU General Public License as published by | |
6 | the Free Software Foundation; either version 3 of the License, or | |
7 | (at your option) any later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | GNU General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
5e8754f9 | 15 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
3d99e817 AK |
16 | |
17 | #if !_LIBC | |
18 | /* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc | |
19 | optimizes away the name == NULL test below. */ | |
20 | # define _GL_ARG_NONNULL(params) | |
21 | ||
22 | # define _GL_USE_STDLIB_ALLOC 1 | |
23 | # include <config.h> | |
24 | #endif | |
25 | ||
26 | #include <alloca.h> | |
27 | ||
28 | /* Specification. */ | |
29 | #include <stdlib.h> | |
30 | ||
31 | #include <errno.h> | |
32 | #ifndef __set_errno | |
33 | # define __set_errno(ev) ((errno) = (ev)) | |
34 | #endif | |
35 | ||
36 | #include <string.h> | |
37 | #if _LIBC || HAVE_UNISTD_H | |
38 | # include <unistd.h> | |
39 | #endif | |
40 | ||
41 | #if !_LIBC | |
42 | # include "malloca.h" | |
43 | #endif | |
44 | ||
45 | #if _LIBC || !HAVE_SETENV | |
46 | ||
47 | #if !_LIBC | |
48 | # define __environ environ | |
49 | #endif | |
50 | ||
51 | #if _LIBC | |
52 | /* This lock protects against simultaneous modifications of 'environ'. */ | |
53 | # include <bits/libc-lock.h> | |
54 | __libc_lock_define_initialized (static, envlock) | |
55 | # define LOCK __libc_lock_lock (envlock) | |
56 | # define UNLOCK __libc_lock_unlock (envlock) | |
57 | #else | |
58 | # define LOCK | |
59 | # define UNLOCK | |
60 | #endif | |
61 | ||
62 | /* In the GNU C library we must keep the namespace clean. */ | |
63 | #ifdef _LIBC | |
64 | # define setenv __setenv | |
65 | # define clearenv __clearenv | |
66 | # define tfind __tfind | |
67 | # define tsearch __tsearch | |
68 | #endif | |
69 | ||
70 | /* In the GNU C library implementation we try to be more clever and | |
71 | allow arbitrarily many changes of the environment given that the used | |
72 | values are from a small set. Outside glibc this will eat up all | |
73 | memory after a while. */ | |
74 | #if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \ | |
75 | && defined __GNUC__) | |
76 | # define USE_TSEARCH 1 | |
77 | # include <search.h> | |
78 | typedef int (*compar_fn_t) (const void *, const void *); | |
79 | ||
80 | /* This is a pointer to the root of the search tree with the known | |
81 | values. */ | |
82 | static void *known_values; | |
83 | ||
84 | # define KNOWN_VALUE(Str) \ | |
85 | ({ \ | |
86 | void *value = tfind (Str, &known_values, (compar_fn_t) strcmp); \ | |
87 | value != NULL ? *(char **) value : NULL; \ | |
88 | }) | |
89 | # define STORE_VALUE(Str) \ | |
90 | tsearch (Str, &known_values, (compar_fn_t) strcmp) | |
91 | ||
92 | #else | |
93 | # undef USE_TSEARCH | |
94 | ||
95 | # define KNOWN_VALUE(Str) NULL | |
96 | # define STORE_VALUE(Str) do { } while (0) | |
97 | ||
98 | #endif | |
99 | ||
100 | ||
101 | /* If this variable is not a null pointer we allocated the current | |
102 | environment. */ | |
103 | static char **last_environ; | |
104 | ||
105 | ||
106 | /* This function is used by 'setenv' and 'putenv'. The difference between | |
107 | the two functions is that for the former must create a new string which | |
108 | is then placed in the environment, while the argument of 'putenv' | |
109 | must be used directly. This is all complicated by the fact that we try | |
110 | to reuse values once generated for a 'setenv' call since we can never | |
111 | free the strings. */ | |
112 | int | |
113 | __add_to_environ (const char *name, const char *value, const char *combined, | |
114 | int replace) | |
115 | { | |
116 | char **ep; | |
117 | size_t size; | |
118 | const size_t namelen = strlen (name); | |
119 | const size_t vallen = value != NULL ? strlen (value) + 1 : 0; | |
120 | ||
121 | LOCK; | |
122 | ||
123 | /* We have to get the pointer now that we have the lock and not earlier | |
124 | since another thread might have created a new environment. */ | |
125 | ep = __environ; | |
126 | ||
127 | size = 0; | |
128 | if (ep != NULL) | |
129 | { | |
130 | for (; *ep != NULL; ++ep) | |
131 | if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=') | |
132 | break; | |
133 | else | |
134 | ++size; | |
135 | } | |
136 | ||
137 | if (ep == NULL || *ep == NULL) | |
138 | { | |
139 | char **new_environ; | |
140 | #ifdef USE_TSEARCH | |
141 | char *new_value; | |
142 | #endif | |
143 | ||
144 | /* We allocated this space; we can extend it. */ | |
145 | new_environ = | |
146 | (char **) (last_environ == NULL | |
147 | ? malloc ((size + 2) * sizeof (char *)) | |
148 | : realloc (last_environ, (size + 2) * sizeof (char *))); | |
149 | if (new_environ == NULL) | |
150 | { | |
151 | /* It's easier to set errno to ENOMEM than to rely on the | |
152 | 'malloc-posix' and 'realloc-posix' gnulib modules. */ | |
153 | __set_errno (ENOMEM); | |
154 | UNLOCK; | |
155 | return -1; | |
156 | } | |
157 | ||
158 | /* If the whole entry is given add it. */ | |
159 | if (combined != NULL) | |
160 | /* We must not add the string to the search tree since it belongs | |
161 | to the user. */ | |
162 | new_environ[size] = (char *) combined; | |
163 | else | |
164 | { | |
165 | /* See whether the value is already known. */ | |
166 | #ifdef USE_TSEARCH | |
167 | # ifdef _LIBC | |
168 | new_value = (char *) alloca (namelen + 1 + vallen); | |
169 | __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1), | |
170 | value, vallen); | |
171 | # else | |
172 | new_value = (char *) malloca (namelen + 1 + vallen); | |
173 | if (new_value == NULL) | |
174 | { | |
175 | __set_errno (ENOMEM); | |
176 | UNLOCK; | |
177 | return -1; | |
178 | } | |
179 | memcpy (new_value, name, namelen); | |
180 | new_value[namelen] = '='; | |
181 | memcpy (&new_value[namelen + 1], value, vallen); | |
182 | # endif | |
183 | ||
184 | new_environ[size] = KNOWN_VALUE (new_value); | |
185 | if (new_environ[size] == NULL) | |
186 | #endif | |
187 | { | |
188 | new_environ[size] = (char *) malloc (namelen + 1 + vallen); | |
189 | if (new_environ[size] == NULL) | |
190 | { | |
191 | #if defined USE_TSEARCH && !defined _LIBC | |
192 | freea (new_value); | |
193 | #endif | |
194 | __set_errno (ENOMEM); | |
195 | UNLOCK; | |
196 | return -1; | |
197 | } | |
198 | ||
199 | #ifdef USE_TSEARCH | |
200 | memcpy (new_environ[size], new_value, namelen + 1 + vallen); | |
201 | #else | |
202 | memcpy (new_environ[size], name, namelen); | |
203 | new_environ[size][namelen] = '='; | |
204 | memcpy (&new_environ[size][namelen + 1], value, vallen); | |
205 | #endif | |
206 | /* And save the value now. We cannot do this when we remove | |
207 | the string since then we cannot decide whether it is a | |
208 | user string or not. */ | |
209 | STORE_VALUE (new_environ[size]); | |
210 | } | |
211 | #if defined USE_TSEARCH && !defined _LIBC | |
212 | freea (new_value); | |
213 | #endif | |
214 | } | |
215 | ||
216 | if (__environ != last_environ) | |
217 | memcpy ((char *) new_environ, (char *) __environ, | |
218 | size * sizeof (char *)); | |
219 | ||
220 | new_environ[size + 1] = NULL; | |
221 | ||
222 | last_environ = __environ = new_environ; | |
223 | } | |
224 | else if (replace) | |
225 | { | |
226 | char *np; | |
227 | ||
228 | /* Use the user string if given. */ | |
229 | if (combined != NULL) | |
230 | np = (char *) combined; | |
231 | else | |
232 | { | |
233 | #ifdef USE_TSEARCH | |
234 | char *new_value; | |
235 | # ifdef _LIBC | |
236 | new_value = alloca (namelen + 1 + vallen); | |
237 | __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1), | |
238 | value, vallen); | |
239 | # else | |
240 | new_value = malloca (namelen + 1 + vallen); | |
241 | if (new_value == NULL) | |
242 | { | |
243 | __set_errno (ENOMEM); | |
244 | UNLOCK; | |
245 | return -1; | |
246 | } | |
247 | memcpy (new_value, name, namelen); | |
248 | new_value[namelen] = '='; | |
249 | memcpy (&new_value[namelen + 1], value, vallen); | |
250 | # endif | |
251 | ||
252 | np = KNOWN_VALUE (new_value); | |
253 | if (np == NULL) | |
254 | #endif | |
255 | { | |
256 | np = (char *) malloc (namelen + 1 + vallen); | |
257 | if (np == NULL) | |
258 | { | |
259 | #if defined USE_TSEARCH && !defined _LIBC | |
260 | freea (new_value); | |
261 | #endif | |
262 | __set_errno (ENOMEM); | |
263 | UNLOCK; | |
264 | return -1; | |
265 | } | |
266 | ||
267 | #ifdef USE_TSEARCH | |
268 | memcpy (np, new_value, namelen + 1 + vallen); | |
269 | #else | |
270 | memcpy (np, name, namelen); | |
271 | np[namelen] = '='; | |
272 | memcpy (&np[namelen + 1], value, vallen); | |
273 | #endif | |
274 | /* And remember the value. */ | |
275 | STORE_VALUE (np); | |
276 | } | |
277 | #if defined USE_TSEARCH && !defined _LIBC | |
278 | freea (new_value); | |
279 | #endif | |
280 | } | |
281 | ||
282 | *ep = np; | |
283 | } | |
284 | ||
285 | UNLOCK; | |
286 | ||
287 | return 0; | |
288 | } | |
289 | ||
290 | int | |
291 | setenv (const char *name, const char *value, int replace) | |
292 | { | |
293 | if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) | |
294 | { | |
295 | __set_errno (EINVAL); | |
296 | return -1; | |
297 | } | |
298 | ||
299 | return __add_to_environ (name, value, NULL, replace); | |
300 | } | |
301 | ||
302 | /* The 'clearenv' was planned to be added to POSIX.1 but probably | |
303 | never made it. Nevertheless the POSIX.9 standard (POSIX bindings | |
304 | for Fortran 77) requires this function. */ | |
305 | int | |
306 | clearenv (void) | |
307 | { | |
308 | LOCK; | |
309 | ||
310 | if (__environ == last_environ && __environ != NULL) | |
311 | { | |
312 | /* We allocated this environment so we can free it. */ | |
313 | free (__environ); | |
314 | last_environ = NULL; | |
315 | } | |
316 | ||
317 | /* Clear the environment pointer removes the whole environment. */ | |
318 | __environ = NULL; | |
319 | ||
320 | UNLOCK; | |
321 | ||
322 | return 0; | |
323 | } | |
324 | ||
325 | #ifdef _LIBC | |
326 | static void | |
327 | free_mem (void) | |
328 | { | |
329 | /* Remove all traces. */ | |
330 | clearenv (); | |
331 | ||
332 | /* Now remove the search tree. */ | |
333 | __tdestroy (known_values, free); | |
334 | known_values = NULL; | |
335 | } | |
336 | text_set_element (__libc_subfreeres, free_mem); | |
337 | ||
338 | ||
339 | # undef setenv | |
340 | # undef clearenv | |
341 | weak_alias (__setenv, setenv) | |
342 | weak_alias (__clearenv, clearenv) | |
343 | #endif | |
344 | ||
345 | #endif /* _LIBC || !HAVE_SETENV */ | |
346 | ||
347 | /* The rest of this file is called into use when replacing an existing | |
348 | but buggy setenv. Known bugs include failure to diagnose invalid | |
349 | name, and consuming a leading '=' from value. */ | |
350 | #if HAVE_SETENV | |
351 | ||
352 | # undef setenv | |
353 | # if !HAVE_DECL_SETENV | |
354 | extern int setenv (const char *, const char *, int); | |
355 | # endif | |
356 | # define STREQ(a, b) (strcmp (a, b) == 0) | |
357 | ||
358 | int | |
359 | rpl_setenv (const char *name, const char *value, int replace) | |
360 | { | |
361 | int result; | |
362 | if (!name || !*name || strchr (name, '=')) | |
363 | { | |
364 | errno = EINVAL; | |
365 | return -1; | |
366 | } | |
367 | /* Call the real setenv even if replace is 0, in case implementation | |
368 | has underlying data to update, such as when environ changes. */ | |
369 | result = setenv (name, value, replace); | |
370 | if (result == 0 && replace && *value == '=') | |
371 | { | |
372 | char *tmp = getenv (name); | |
373 | if (!STREQ (tmp, value)) | |
374 | { | |
375 | int saved_errno; | |
376 | size_t len = strlen (value); | |
377 | tmp = malloca (len + 2); | |
378 | /* Since leading '=' is eaten, double it up. */ | |
379 | *tmp = '='; | |
380 | memcpy (tmp + 1, value, len + 1); | |
381 | result = setenv (name, tmp, replace); | |
382 | saved_errno = errno; | |
383 | freea (tmp); | |
384 | errno = saved_errno; | |
385 | } | |
386 | } | |
387 | return result; | |
388 | } | |
389 | ||
390 | #endif /* HAVE_SETENV */ |